Why is success in worldly matters (such as marriage and work) not achieved, despite striving in acts of obedience and drawing closer to God?

A believer must be content with Allah's decree and destiny, for Allah is All-Wise, placing things in their rightful positions, and He decrees nothing except with profound wisdom and great benefit, even if this benefit is hidden from His servant. Allah decrees nothing but good for the believer, and the believer should not entertain ill thoughts of Allah. Most people think ill of Allah, believing that their rights are diminished and that they deserve more than what Allah has given them, whereas they should think ill of themselves, for they are the source of evil. Giving and withholding in this world are not signs of Allah's pleasure or displeasure. The true matter is patience with Allah's judgment and striving in supplication. Any perplexing questions that arise in one's mind are from the whispers of Satan, and one should not listen to them.